Response and performance of a test pavement to freeze/thaw cycles in the Danish Road Testing Machine

摘要

A freeze/thaw experiment was conducted on the second test pavement (RTM-2), which was constructed and used for accelerated load testing in the preceding international study. The experiment consisted of two freeze/thaw cycles, during which temperatures in the pavement layers were constantly monitored. The soil pore pressures in the Subgrade, the responses of the pavement materials and the pavement surface profiles were also measured during the accelerated load testing (ALT) carried out in the thawing periods. During the accelerated load testing, the dynamic responses increased slightly, while the vertical plastic strains in the unbound granular materials (UGM) increased sharply. It is suggested that during the thawing periods, under the action of the applied loads, the majority of the plastic (permanent) strains in the unbound granular materials are due to the movement, reorientation and resettlement of the particles of these materials. An energy-density model developed in the preceding study to estimate plastic strains in the Subgrade is introduced; it is suggested that an additional parameter, or parameters, is required to better describe the soil strength, or soil conditions, during thawing. The model variant used to predict pavement functional performance, satisfactorily predicts pavement functional performance under accelerated loading during thawing periods.